BIO 1150 Exam 1 - Questions with Verified Answers

BIO 1150 Exam 1 - Questions with Verified Answers Postzygotic barrier A reproductive barrier that prevents hybrid zygotes produced by two different species from developing into viable, fertile adults Morphological species concept A definition of species in terms of measurable anatomical criteria. Ex. body shape and other structures Ecological species concept A definition of species in terms of ecological niche, the sum of how members of the species interact with the nonliving and living parts of their environment. Allopatric separation Where a population forms a new species while geographically isolated from its parent population. Restricted gene flow Sympatric separation A subset of a population forms a new species without geographical separation Polyploidy When an organism has extra sets of chromosomes Autopolyploid An individual that has more than two chromosome sets that are all derived from a single species Allopolyploid A fertile individual that has more than two chromosome sets as a result of two different species interbreeding and combining their chromosomes. Hybrid zone A geographic region in which members of different species meet and mate, producing at least some offspring of mixed ancestry Reinforcement Natural selection strengthens prezygotic barriers to reproduction, reducing the chances of hybrid formation Fusion Causes two hybridizing species to fuse into a single species Stability Hybrids continue to be produced, sometimes surviving and reproducing better than members of either parent species Punctuated equilibria Long periods of little apparent morphological change interrupted by relatively brief periods of sudden change By what rate does speciation occur? Once the process begins, it can be completed relatively rapidly Limitations of the biological species concept Can't use on fossils Often lack information Does not account for sexual reproduction Factors that prevent offspring formation (pre-zygotic barriers) -Habitat isolation -Temporal isolation (time) -Behavioral isolation (song) -Mechanical isolation (anatomical) -Gamete incompatibility Factors that prevent offspring survival and reproduction (post-zygotic barriers) -Lack of viable offspring (death) -Lack of fertile offspring (sterility) Phylogeny Evolutionary history of a species or group of related species. Systematics